Resistance switching effect regulated by magnetic field in Ni/ZnO/BiFeO₃/ZnO multilayers

Abstract

The 21st century is an era of information. In recent years, people’s demand for better data storage performance and stronger data processing capacity of memorizer has been increasing, which has prompted continuous improvement and innovation of semiconductor integrated processes and technologies and accelerated the research progress of the next generation of memory devices to break through the limits of Moore’s law. Resistive memory has been regarded as an important candidate for the next generation of non-volatile random access memory due to its main characteristics such as fast reading speed, high storage density, long storage time, low power consumption, and simple structure. Resistive switching effects have been observed in various transition metal oxides and complex perovskite oxides, but the appropriate description of the resistive switching drive mechanism is still an important issue in the development of resistive random access memories. Therefore, further research is very important to clearly explain the phenomenon of resistance switching. With the demand for data storage and sensor applications increasing, materials with excellent ferroelectric and ferromagnetic properties have attracted great attention. The ZnO is an important semiconductor material with excellent optical and electrical properties. Bismuth ferrate (BiFeO₃) has received much attention due to its excellent properties in epitaxial and polycrystalline thin films, with hundreds of publications devoted to it in the past few years. The ZnO and BiFeO₃ are both important electronic materials and have important application value. Therefore, ZnO/BiFeO₃/ZnO structure is adopted in this work to study the resistance switch characteristics. The resistance conversion effect in ZnO/BiFeO₃/ZnO structure is measured. In this work, the Ni/ZnO/BiFeO₃/ZnO/ITO multilayer nano-film storage device is prepared by magnetron sputtering coating technology. The device is characterized by X-ray diffractometer, scanning electron microscope and other equipment, and its resistance performance is further tested by Keithley 2400. The device exhibits obvious bipolar resistance switching effect, and the resistance switching characteristics of the sample, including switching ratio, tolerance and conductivity, vary significantly with the interference of the applied magnetic field. The bipolar resistance switching effect can be explained by the capture and release of oxygen vacancies trapped inside the material. The effect of magnetic field on Ni/ZnO/BiFeO₃/ZnO/ITO thin film device should be attributed to the change of schottky barrier at Ni/ZnO interface, caused by magnetic field.